With the sun well below the horizon and the late autumn dusk rapidly falling, the chorus of Great-horned Owl calls rose from the cottonwoods, seeming to emanate from all directions at once. Surrounded by the hauntingly beautiful sound of owls, we slowly made our way along the road toward home. We had just left behind a pair of Short-eared Owls, after watching them hunt over the grassland for nearly an hour. Rounding the bend, I spotted our third owl species of the evening, a small round-headed gnome, hunched in the grasses.
Burrowing Owls inhabit grasslands and other open areas across the western United States, where they are found in association with high densities of burrowing animals like ground squirrels and prairie dogs. Since most Burrowing Owls don't actually excavate their own burrows, they rely on other species to do the bulk of the digging for them. When moving into an existing burrow, however, the small owls do make some renovations, enlarging openings and maintaining chambers by digging with their bills and feet.
Nonmigratory Burrowing Owl populations, such as those in California's San Joaquin Valley, utilize burrows year-round, while those that migrate south for the winter tend to be more nomadic, roosting in clumps of vegetation and using burrows only during the nesting season. Breeding pairs of Burrowing Owls, which are typically monogamous, stay together throughout the year, and those that do not migrate stay near their burrow.
Most of the prey taken by Burrowing Owls are invertebrates, such as crickets, grasshoppers, centipedes, beetles and the like, though they are not fussy and will eat just about anything they are able to catch, including small mammals, like mice and voles, as well as frogs and toads, lizards and snakes, and even other small birds.
As they breed in loose colonies, where there is one Burrowing Owl there are usually more! The evening we encountered the owls in the photos above, I counted at least four individual Burrowing Owls.
The picture below, taken on a different visit to Merced NWR, shows how similar in size and color Burrowing Owls are to California Ground Squirrels, the species whose burrows the owls use most commonly in California. Because of this, it is always worthwhile to stop and scan a ground squirrel colony, just in case a Burrowing Owls is hiding out in their midst!
Burrowing Owls may be active at any time of day or night, though during the day they tend to roost quietly near their burrow - unless of course they have a hungry brood of young owlets to feed! Then their daily antics are often on display for the curious observer. (But be respectful and keep your distance! Burrowing Owls are popular and often obliging little creatures, and there have been many unfortunate cases in which hoards of photographers have pushed too far, to the detriment of the owl families.)
Like most grassland species, Burrowing Owls are threatened by habitat loss and many populations have decreased or been wiped out entirely. They also suffer greatly due to the elimination of the burrowing mammals they depend on, like the ground squirrels and prairie dogs that have been ruthlessly exterminated by farmers and ranchers across the West. As ground nesters in open and often disturbed sites, they are at the mercy of powerful agricultural equipment, the drivers of which can easily eliminate entire nesting colonies without even knowing! Poisoning from pesticides is also a grave threat to all owls, not just the Burrowing Owl. In California, it is considered a Species of Special Concern.
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